An analytical high performance liquid chromatographic method for the determination of agnuside and p-hydroxybenzoic acid contents in agni-casti fructus

Since there is an increasing interest in Agni-casti preparations, their sta ndardisation is becoming more important. The significant components agnusid e and casticin are the most suitable for standardisation, the former being a chemotaxonomic marker of the genus Vitex L. and also being commercially a vailable. The analytical method developed includes not only the determinati on off agnuside but also of p-hydroxybenzoic acid (PHBA), which may be of s ome interest because agnuside is composed of aucubin and PHBA, Fruits of Vi tex agnus-castus were extracted twice with methanol, the extracts combined, evaporated to dryness and dissolved in water:methanol (95:5), This solutio n was subjected to solid phase extraction over neutral aluminium oxide in o rder to remove co-occurring, and interfering, isoorientin. Agnuside was ass ayed by high performance liquid chromatography on a Cls-column eluted with an acetonitrile:water gradient and detected at 258 nm using a diode array d etector. Agnuside was observed between 7.8 and 8.1 min and PHBA between 2.0 and 2.3 min, Eight plant samples were investigated. Copyright (C) 2000 Joh n Wiley & Sons, Ltd.